In wireless communications, techniques exist to improve spectral efficiency. For example, receivers are provided with hardware which carry out techniques such as QR demodulation, or MLD (maximum likelihood detection). However, many of these receivers are complex.
Existing methods allow two independent data streams, for example: 2 transmit-2 receive antenna (2×2) multiple input-multiple output (MIMO) systems using a 2×2 QR-MLD demodulator. A problem arises when it is desired to extend the 2×2 QR-MLD demodulator to handle four independent data streams (e.g. a 4×4 MIMO system) or even eight independent data streams (e.g. 8×8 MIMO system) since it is not straightforward. This is due to the complexity of the hardware implementation associated with a 4×4 demodulation scheme where MLD is applied. This hardware complexity in turn leads to a larger chip size and increased power consumption.
This problem is exacerbated by the need for present receivers in wireless communication systems to be able to demodulate transmitted data with a variety of different methods.
It would therefore be desirable to provide a method of demodulating transmitted data for 4×4 MIMO systems or 8×8 MIMO systems which can utilize existing 2×2 demodulators but without complexity.
It will be appreciated that a reference herein to any matter which is given as prior art is not to be taken as an admission that that matter was, in Australia or elsewhere, known or that the information it contains was part of the common general knowledge as at the priority date of the claims forming part of this specification.